In Singapore in particular, the weather is 60% hot, 30% humid and 10% unpredictable showers. So traveling to Singapore requires you to pack mainly cooling and comfortable attire.
These are your best weapons against the hot sun in Singapore! However, remember that you are on holiday so make sure it doesn't look too torn and tattered!
Singapore has the best streets to spend your day walking through. (Psst.. it's even better on our cycling tours) So ditch the high heels and leather shoes, pick up the flip flops and you will enjoy the journey better!
I'll be frank. Singapore's weather is as unstable as the stock market. One moment it may be sunny and bright, the next moment showers would hit with no warning. So should you bring an umbrella or poncho? Advise is to skip the brollies! Singapore's infrastructures are build well to have sheltered walkways linking public transportation to buildings, buildings to food centres and food centres to... well you get the point. There are shelters everywhere! So pack light and do without the umbrellas, furthermore you can just buy a cheap and good one off the rack.
In Singapore, we use 3 pin UK socket. If your adaptor monster looks any lesser than 3 rectangle heads, go get an adaptor!